From DE-PS 25 22 670 it is known to axially secure the cage of a constant velocity fixed joint via a supporting disc secured at the open end of the outer joint part. It is the object of the above publication to facilitate assembly by using an undercut-free outer joint part.
The disadvantage of the design described is that the balls in the running tracks run with play and that only the axial play of the cage can be set. This necessarily means that there exists play between the inner joint part, the ball and the outer joint part on the one hand and between the inner joint part, the cage and the outer joint part on the other hand.
This means that there are two sequences of play of which, as illustrated in FIG. 1 of the said publication, only one sequence, i.e. the axial play between the cage and outer joint part can be set.
Furthermore, it has been proposed (DE-OS 3721775) to guide the cage by a so-called supporting disc so as to be pivotable around the joint center, with the supporting disc being received in a holding ring and being able to move therein in a radially floating way.
The disadvantage of this design is that by arranging the holding ring and supporting disc in front of the open axial end of the outer joint part the possible angle of articulation may be adversely affected.
A constant velocity universal joint with wedge-shaped supporting elements for axially securing the cage is known (German Patent Application 42032195.8). The disadvantage of the design described is that the supporting inserts have to be secured individually.
As the supporting inserts are very small, handling during the fixing and welding operation is extremely complicated.
There is a further prior art design as described in DE-PS 3233753 where the inner face of the outer joint part is partially stepped relative to the spherical outer face of the cage.
However, this publication does not propose any measures for setting the play.
The play values resulting from production tolerances may add up in a disadvantageous way, thereby resulting in increased joint wear.
It is the object of the present invention to provide a constant velocity fixed joint in the case of which the two sequences of play are defined and are capable of being set to a specified value. At the same time, assembly is to be simplified by axially introducing the inner joint part together with the cage and the inserted balls.
In accordance with the invention, the objective is achieved in that the balls are held in a clearance-free way in the outer running grooves and in the inner running grooves, that a ring is provided with at least two fingers pointing axially and radially inwardly into the cavity of the outer joint part and held between two outer running grooves so as to abut the spherical outer face of the cage. The ring is arranged at an axial distance(s) from a reference face located at the open end of the outer joint part, and that the ring, while observing a predetermined axial play relative to the cage, is connected to the outer joint part, with the inner faces of the outer joint part arranged between the outer running grooves being held at a distance from the spherical outer face of the cage.
The advantage of the design in accordance with the invention is that the ring, with the fingers supporting the cage, is connected to the outer joint part in a position where it is aligned relative to the cage. In this way it is ensured that all cumulative errors occurring in the joint are eliminated.
By providing a play(s) while the ball contact the outer and inner running grooves in a clearance-free way, it is ensured that a predetermined axial play can be determined very accurately.
By designing the joint in accordance with the invention, very clear conditions are obtained for the play values existing in the joint. The first sequence of play between the outer joint part, the balls and the inner joint part is set to zero and the second sequence of play between the outer joint part, cage and inner joint part is suitable for being set.
In this way, both sequences of play are clearly defined.
According to an advantageous embodiment of the invention, the fingers starting from the ring are arranged radially inwardly, with the fingers of the ring secured to the outer joint part being crimped in the direction of the cavity.
The advantage of this design is that the ring together with the fingers may be punched out of a plate metal material and the fingers are then bent, which means that the ring can be produced very cost-effectively.
According to a further essential feature of the invention, the fingers are designed as wedge-shaped supporting projections pointing away approximately axially from the ring.
This design allows the supporting inserts to contact the spherical outer face of the cage over a relatively large area.
In a further embodiment of the invention, the outer joint part, at a radial end face associated with its open end, is provided with a radially inner recess serving to receive the ring, the inner diameter of the recess being greater than the outer diameter of the ring.
With this design, the ring may easily be fixed to the outer joint part by welding, for instance by laser welding in the axial direction of the joint, which means that it is possible to automate the welding operation.
According to a further embodiment, the ring is provided with a projection coaxially embracing the outer circumference of the outer joint part.
With this design, too, the ring may easily be welded to the outer joint part.
In a further advantageous embodiment of the invention, the coaxial projection of the ring is used as a seat for a convoluted boot secured to the outer joint part.
As a result of this measure, it is easy to fix the convoluted boot to the coaxial projection of the ring.
According to a further embodiment of the invention it is proposed that the diameter of the ring should be greater than the outer circumference of the outer joint part and that the part of the ring projecting beyond the outer circumference of the outer joint part should be used as a stop for a convoluted boot secured to the outer circumference of the outer joint part.
This design permits an inexpensive and easy possibility of fixing the convoluted boot to the outer joint part.
In a preferred embodiment of the invention it is proposed that the outer joint part, at its open axial end, is provided with at least two radially extending grooves, that a closed ring is secured in the radially outer region and that the ring is provided with fingers which correspond to the grooves, which pass radially through the grooves and which are held so as to abut the spherical face of the cage.
With this design, the ring, including the fingers, is integrated into the axial length of the outer joint part so that the maximum articulation angle is not limited in any way.
According to a further advantageous feature, the outer joint part, at its open axial end, is provided with a continuous step and the radially outer free space produced by the step is intended to receive the ring.
As a result, it is easy to weld the ring to the outer joint part.
According to a further embodiment of the invention, the ring is produced from a radially extending flat material and welded via a V-weld to the outer circumference of the outer joint part.
Again, it is easy to secure the ring to the outer joint part.
According to a further advantageous embodiment of the invention, the ring is designed as a ring which extends coaxially relative to the joint axis, which embraces the outer circumference of the outer joint part and is welded thereto via a fillet weld, with the fingers being angled relative to the joint axis.
According to a further feature of the invention, the fingers, starting from the inwardly directed radial direction, are additionally angled approximately axially towards the center of the joint, and the angled web is adapted to the spherical outer face of the cage. This design permits the fingers to contact the spherical outer face of the cage over a large area.
According to a further feature of the invention, the fingers are designed approximately box-like as hollow profiles, and the contact face is adapted to the spherical outer face of the cage.
With this design, the fingers are able to support high axial forces acting on the cage.
In a further embodiment, the fingers are designed as solid profiles with a rectangular cross-section, with the radially inner faces of the fingers being adapted to the spherical outer face of the cage.
In accordance with another embodiment of the invention, the objective is achieved in that the outer joint part is provided with recesses arranged between the outer running grooves, that wedge-shaped inserts serving to axially secure the cage and being connected to one another by an annular strip are inserted into the recesses and that the wedge-shaped inserts are welded to the outer joint part in the recesses and that after the welding operation the annular strip is removed from between the wedge-shaped supporting inserts.
The advantage of the method proposed in accordance with the invention consists in that while the wedge-shaped supporting inserts are in the process of being secured they are, without fail, easy to handle and that by separating the parts of the annular strip positioned between the wedge-shaped supporting inserts it is ensured that the maximum angle of articulation is not adversely affected.
According to an essential feature of the invention, the regions of separation of the annular strip are predetermined by nominal fracture regions provided at both ends of the supporting inserts.
The nominal fracture regions ensure a clean line of separation at both ends of the supporting inserts thereby eliminating any need for remachining.
According to a further advantageous embodiment of the invention, the annular strip, for the purpose of being positioned in a true-to-angle way, is provided with recesses corresponding to the balls in the aligned position.
These recesses permit the annular strip provided for fixing purposes to be positioned and aligned in a simple and accurate way.